Tipped off by concerned family, police arrived at the apartment of the suspect in Friday’s deadly shooting at Los Angles International Airport less than an hour after he left for his shooting spree, according to a lawmaker briefed on the matter.

Texas Republican Rep. Michael McCaul, who chairs the House Homeland Security Committee, said Sunday on CNN that cops got to Paul Ciancia’s apartment just 45 minutes after he had left for the airport. Ciancia opened fire with an assault rifle near a security checkpoint Friday morning, killing one Transportation Security Administration agent and wounding others before being taken into custody, police said.

Ciancia had sent text messages to his family saying he was unhappy and suggesting something bad would happen, authorities said. His father in New Jersey was concerned enough to call local police, who reached out to the Los Angeles Police Department. Los Angeles cops arrived after he left, but his two roommates didn’t know where he had gone, McCaul said.

A third roommate had driven Ciancia to the airport, but investigators don’t think the roommate knew of the shooter’s motives, CNN reports, citing an unnamed source.

Ciancia, 23, was charged Saturday with murder of a federal officer and commission of violence in an international airport. He remains hospitalized in critical condition.

*Update: The Associated Press reports at least one FBI agent returned to Ciancia’s apartment on Monday. A man was escorted out and he later drove off in a black Hyundai, the same car agents allege was used to drive Ciancia to LAX on Friday prior to the shooting. The FBI did not identify the man nor did they comment on the investigation.